Communication system network interconnecting a plurality of communication systems

ABSTRACT

The present invention discloses a communication system network that comprises a plurality of communication systems and a processing multiplexer. The communication systems, which may be either conventional communication systems and/or trunked communication systems, transmit digitized audio signals and communication system data to the processing multiplexer. Based on signal destination data, which is part of the communication system data, the processing multiplexer processes the digitized signals and routes the resultant signals to the appropriate signal destinations of the communication systems.

TECHNICAL FIELD

This invention relates generally to communication systems and inparticular to a method and apparatus that allow such communicationsystems to be linked together to create a communication system network.

BACKGROUND OF THE INVENTION

Presently, there are two basic types of land-mobile communicationsystems: conventional communication systems (FIG. 1) and trunkedcommunication systems (FIG. 2). Each type of communication systemcomprises a plurality of communication units, a limited number ofcommunication resources, a communication resource allocator, and aplurality of operator stations (consoles). The communication resourceallocator comprises a plurality of base interface modules (BIMs), aplurality of operator mux interface modules (OMIs), a plurality of audioexpansion interface modules (AEIs), and at least one TDM bus. Each BIMacts as both a signal source and a signal destination. As a signalsource, the BIM receives audio signals from at least some of theplurality of communication units, via a repeater or base station,converts the signals into digitized signals, and sources them to a slotin the TDM bus. See FIG. 3 for a typical TDM slot assignment pattern.(For an operational description of the TDM bus and slot location, referto Motorola, Inc., Pub. No. R4-2-37C, CENTRACOM Series II ControlCenters (March, 1988).) The BIM also acts as a designated signal sourceby conveying communication system data that it produces or is producedby a communication unit to the rest of the communication system. As asignal destination, the BIM receives digitized signals from the TDM bus,converts them to audio signals, and sends the audio signals to arepeater or base station such that the audio signals may be transmitted,via a communication resource, to at least some of the plurality ofcommunication units.

Within either type of communication system, an OMI and an AEI are usedto interface a console to the rest of the system. Generally, the OMIcontains, in firmware, information that allows its respective console toperform supervisory functions and information that pertains to thecommunication system configuration. The communication systemconfiguration information, or data, includes, but is not limited to, thenumber of repeaters, number of signal sources, the number of signaldestinations, the TDM slot assignments for each signal source and signaldestination, the type of each BIM, and destination information, or data.(For a detailed description of and a list of supervisory functions,refer to Motorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II PlusControl Centers (April, 1988). However, for use herein, consoles neednot incorporate all of the described features as listed in the CENTRACOMSeries II Plus Control Centers publication.) The OMI, as a designatedsignal source, sources communication system data to the TDM bus, whereinthe communication system data comprises information about thecommunication system configuration, information about selectedsupervisory functions, and/or information about selected signaldestinations. The OMI further acts as a signal source by receiving audiosignals from its respective console, converting the signals intodigitized signals, and sourcing the digitized signals, in theappropriate slot, to the TDM bus.

The OMI, however, does not act as a signal destination for itsrespective console, the AEI performs this function. The AEI, as a signaldestination, receives digitized signals from the TDM bus, converts thesignals into audio signals, and sends the audio signals to a speakerthat is controlled by an assigned channel control module (CCM) of theconsole. (For a detailed description of CCMs, refer to Motorola, Inc.Pub. No. R4-2-73, CENTRACOM Series II Plus Control Centers (April,1988).) The audio signals sent to the speaker may comprise a pluralityof audio signals that were generated by several signal sources, suchthat the operator of the console may monitor and supervise severalsignal source via one speaker and one CCM per signal source. The AEIacts as a signal destination for each CCM on a console, thus if aconsole has ten CCMs, the AEI acts as ten signal destinations. It shouldbe noted that the actual signal sources and signal destinations are thecommunication units and console, however, they are addressed by theirrespective communication system interfacing modules (BIMs, OMIs, andAEIs). Thus, for the purposes this discussion, the OMIs and BIMs will bereferenced as signals sources, while the AEIs and BIMs will bereferenced as signal destinations.

As described above, conventional communication systems and trunkedcommunication systems have several characteristics alike, however, eachcommunication system operates in a distinct mode. The typicalconventional system of FIG. 1 comprises a plurality of communicationunits, a plurality of repeaters that transceive information viacommunication resources, a communication resource allocator (centralelectronics bank (CEB)), and a plurality of consoles. Also shown is acomputer aided dispatcher (CAD) which may also be incorporated intotrunked communication system. (For a description of the CAD, refer toMotorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II Plus ControlCenters (April, 1988).) The communication system configuration of aconventional communication system has communication groups assigned tospecific repeaters, wherein specific consoles are assigned to monitorsome of the communication groups. (A communication group comprises atleast some of the plurality of communication units that are typicallyused for like purposes, e.g. police department, fire department, etc.)The repeater and communication group assignments may be changed by aCAD, but regardless of the assignments, a console monitors only therepeaters having at least one of its communication group assigned to it.For a further discussion of the conventional communication system referto U.S. Pat. No. 4,630,263, entitled TIME DIVISION MULTIPLEXCOMMUNICATION CONTROL SYSTEM, assigned to Motorola, Inc.

The typical trunked communication system of FIG. 2 comprises a pluralityof communication units, a plurality of repeaters that transceive signalsvia communication resources, a communication resource allocator, and aplurality of consoles. (As with a conventional communication system, thecommunication resources may be telephone lines, frequency pairs, carrierfrequencies, or TDM slots.) The typical communication systemconfiguration of the trunked communication system comprises thecommunication units arranged into a plurality of communication groups,where the repeaters are allocated to a communication group upon request.The consoles are assigned to monitor specific communication groups,however, the console cannot monitor a specific repeater as in aconventional communication system. The console must receive informationfrom the communication resource allocator about the repeater that hasbeen allocated to one of its communication groups. For a furtherdescription of the trunked communication system refer to U.S. Pat. No.4,698,805 entitled CONSOLE INTERFACE FOR A TRUNKED RADIO SYSTEM,assigned to Motorola, Inc.

Despite all the features that each communication system offers tosubscribers (user of a communication unit) and console operators, theiruse is limited to the communication system that the subscribers and/orconsole operators are affliated with. This may be a substantial limitingfactor in large metropolitan areas having a large number of subscribersand console operators. For example, if a city has a large police force,fire department, and other civil service departments, severalcommunication systems may be needed to adequately service them. Becausecommunication systems may not actively communicate with othercommunication systems, the city must have several central controlstations instead of one. For example, if the city has thirtycommunication systems with the police force subscribing to several ofthe systems, the city's police force may not all communicate together,nor can one console operator send a supervisory message to the entirepolice force. Therefore, a need exists for a communication systemnetwork that allows communication units in either type of communicationsystem to communicate with other communication units in the same ordifferent communication systems and that allows console operators tomonitor and supervise communication groups in its communication systemas well as communication groups in other communication systems.

SUMMARY OF THE INVENTION

These needs and others are substantially met by the communicationnetwork that comprises a processing multiplexer and a plurality ofcommunication systems disclosed herein. Each of the communicationsystems comprises a plurality of signal sources and a plurality ofsignal destinations, wherein at least some of the signal sources producesignals and wherein designated signal sources of the plurality of signalsources produce communication system configuration data. The processingmultiplexer comprises a plurality of communication ports, signaldatabase circuitry that stores information pertaining to the signalsproduced by at least some of the signal sources, system data databasecircuitry that stores information pertaining to the communication systemconfiguration data produced by the designated signal sources, andprocessor circuitry that processes at least a part of the informationpertaining to the signals stored in the signal database based on, atleast in part, the communication system configuration data stored in thecommunication system database.

An aspect of the communication system network includes a receivingcircuit within the processing multiplexer that receives the signalsproduced by the signal sources and that receives the communicationsystem data produced by the designated signal sources. Once received,the receiving circuit sends information pertaining to the signals to thesignal database circuitry and sends information pertaining to thecommunication system data to the data database circuitry.

Another aspect of the communication system network includes anaddressing circuit within the processing multiplexer that generatesaddresses for the received information pertaining to the signals and forthe received information pertaining to the communication system data.The generated addresses are used to store the information pertaining tothe signals at addressable locations within the signal databasecircuitry and to store the information pertaining to the communicationsystem data at addressable locations within the system data database.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a typical conventional communication system of theprior art.

FIG. 2 illustrates a typical trunked communication system of the priorart.

FIG. 3 illustrates a diagram of a TDM bus of the prior art.

FIG. 4 illustrates a communication system network in accordance with thepresent invention.

FIGS. 5A, 5B, and 5C illustrates a TDM slot arrangement of the sourceinterface bus and the destination interface buses.

FIG. 6 illustrates a circuit diagram of an ambassador board.

FIG. 7 illustrates a circuit diagram of an ambassador interfacemultiplex interface board. FIG. 8 illustrates a logic diagram of aprocess for producing addresses for the destination database.

FIG. 9 illustrates a logic diagram of a process for producing addressesfor the signal database.

FIG. 10 illustrates a portion of the destination database having exampledata stored therein.

FIG. 11 illustrates a portion of the signal database having example datastored therein.

FIG. 12 illustrates a logic diagram of a process for updating eachcommunication system's communication system configuration database.

FIG. 13 illustrates a logic diagram of a process for controlling accessto the AEB data bus.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 4 illustrates a communication system network that comprises aplurality of communication systems (401) and a processing multiplexer orambassador electronics bank (AEB) (402). The plurality of communicationsystems (401) may comprise conventional communication systems and/ortrunked communication systems. The AEB (402) comprises a plurality ofambassador boards (403), a system synchronization circuit (404), an AEBdata bus (405), AEB signal buses (406), and a plurality of communicationports (407). Each of the ambassador boards (403) comprises a receivingdecoder (408), a detection circuit (409), communication system databasecircuitry (410), an address circuit (411), a processing circuit (412), asending circuit (413), signal database circuitry (414), an address bus(415), and a plurality of interconnection buses (416). Each of theplurality of communication systems (401) is coupled to a communicationport (407) by at least one source interface bus (426) and at least onedestination interface bus (427). Each communication system (401)comprises an ambassador interface mux interface module (AIMI) (417), aplurality of signal sources (418), a plurality of signal destinations(419), a data bus (420), a source bus (421), and a destination bus(422). The AIMI (417) comprises a sending circuit (423), a receivingcircuit (424), and a processing circuit (425).

Generally, within the AEB (402), each ambassador board (403) is operablycoupled to at least one communication port (407), to the AEB data bus(405), and to the AEB signal buses (406). The best mode contemplatesthat each ambassador board (403) will be coupled to two communicationports (407), such that each ambassador board may service twocommunication systems (401). To achieve this, the ambassador board (403)would include a second receiving decoder (not shown) and a secondsending encoder (not shown) and be connected to another communicationport (407). Within the ambassador board (403), the second receivingdecoder and the second sending encoder would be connected to the signaldatabase circuitry (414), the detection circuit (409), the system datadatabase circuitry (410), and the addressing circuit (411) in a similarfashion as the first sending encoder (413) and first receiving decoder(408). Because the second receiving decoder and the second sendingencoder operate in a similar fashion as the first receiving decoder(408) and the first sending encoder (413), respectively, only theoperation of the first receiving decoder (408) and the first sendingencoder (413) will be discussed.

Upon receiving signals and communication system data from acommunication system, via a source interface bus (426), the receivingdecoder decodes and separates them. (A more detailed description of thereceiving decoder's operation and the format of the source interface buswill be discussed below.) The separated signals are placed on one of theAEB signal buses (406) and the separated communication system data isrouted to the system data database circuitry (410). The AEB signal buses(406) comprises thirty-two individual buses, each bus being dedicated toa communication system, such that the separated signals are placed onthe bus dedicated to the communication system that produced the signals.The dedication of AEB buses (406) to communication systems (401) isdetermined by which communication port the communication system isoperably coupled to. Thus, the communication system (401) that iscoupled to the first communication port (407) has the first AEB busdedicated to it. A more detailed discussion of the AEB signal bus tocommunication system assignments will be presented below.

The separated signals produced by each of the communication systems(401), are synchronously placed on their respective AEB signal bus(406). (A detailed description of the communication system networksynchronization process will be discussed below.) Each signal databasecircuitry (414) is coupled to all the AEB signal buses (406) and, forthis portion of the synchronization period or predetermined time frame,stores each of the separated signals in a signal database as an eightbit PCM code. The best mode contemplates that each signal database willbe a dual port random access memory device (DPRAM), nevertheless, anyreprogrammable memory device will suffice. The signal database may storeeach of the signals as information pertaining to them, if a differentcoding scheme of the signals is employed, such as a linearrepresentation or other digital representation. (A detailed descriptionof the signal database circuitry (414) will be discussed below.)

The separated communication system data is routed to the system datadatabase circuitry (410). The separated communication data generallycomprises information about the typical communication systemconfiguration (i.e. the number of repeaters, number of signal sources,the number of signal destinations, the TDM slot assignments for eachsignal source and signal destination, the type of each BIM, anddestination information, or data) and information about selectedsupervisory functions. The communication system configurationinformation is stored in a destination database, while othercommunication system data is stored in RAM or similar reprogrammablememory device. The best mode contemplates that each destination databasewill be DPRAM, nevertheless, any reprogrammable memory device willsuffice. The communication system data that is stored in RAM issubsequently placed on the AEB data bus (405). (A detailed descriptionof the system data database circuitry (410) will be discussed below.)

The addressing circuit (411) produces addresses for the separatedsignals and for the separated communication system configuration data.The addresses are used by the signal database circuitry (414) and thesystem data database circuitry (410) to store the respective informationin identifiable locations. The address for each signal is representativeof the communication system that it is from and the signal source thatgenerated it. For example, if the signal was generated by the thirdsignal source of the fifteenth communication system its address may be01111 00011. A more detailed discussion of generating addresses for boththe signal database and the destination database will be presentedbelow.

Once the signals are stored in each of the signal databases and once thecommunication system configuration data is stored in the respectivesystem data database circuit, the processing circuit (412) in eachambassador board (403) processes the stored signals based on, at leastin part, on the stored communication system configuration data. Theprocessing of the stored signals typically involves producing processedsignals for each of the signal destinations of the communication systemcoupled to the ambassador board (403) which typically occurs withinpredetermined number of frame cycles. The processed signals typicallycomprise a summation of signals that the signal destination is toreceive, wherein the volume levels of each of the summed signals may bevaried. (A detailed description of the processing circuit will bediscussed below.)

In a subsequent predetermined number of frame cycles, the processedsignals are routed to the sending encoder (413) of the ambassador board(403) which, at least, encodes the processed signals. Once theinformation is encoded, it is placed onto the destination interface bus(427). The best mode contemplates that the destination interface bus(427) will comprise two buses, such that each communication system mayhave twice as many signal destinations as signal sources.

The master synchronization circuit (404) of the AEB (402) generates, atleast, a master clock signal and a frame sync signal. The best modecontemplates that the master clock signal will have a frequency of about2.048 MHz and the frame sync signal will have a frequency of about 8KHz. Each communication system receives the master clock signal and theframe sync signal from the master synchronization circuit (404) andreconstructs it to produce its own clock signal of about 2.048 MHz andown frame sync signal of about 8 KHz. Synchronization buffers are usedto compensate for propagation delays between the communication systemsand the AEB, operation of the synchronization buffers will be discussedbelow. Due to the propagation delays between the communication systemsand the AEB, it takes several frame sync signals to receive signals fromsignal sources, process the received signals, and route the processedsignals to the appropriate signal destinations. The best modecontemplates that it will take about eleven frame cycles from the time asignal is produced until a processed signal of that signal is receivedby the appropriate signal destination: two for producing and placingsignals on the source interface bus, two for receiving and placing thesignals on the AEB signal buses (406), two for storing the signals inthe signal database, one for processing the signals, two for placing theprocessed signals on the destination interface buses (427), and two forrouting the processed signals to the respective signal destinations.

Generally, within each communication system (401), the AIMI (417) isoperably coupled to the plurality of signal sources (418) and theplurality of signal destinations (419) via a TDM data bus (420), a TDMsource bus (421) and two TDM destination buses (422) (only one shown).As mentioned, the plurality of signal sources (OMIs and/or BIMs) receiveaudio signals generated by communication units and/or consoles andconverts the signals into digitized audio signals. The digitized audiosignals are placed on the TDM source bus (421) in the slot assigned tothe particular OMI or BIM. (See FIG. 3 for a graphic representation ofslot assignments.) At least some of the OMIs and/or BIMs, as designatedsignal sources, generate communication system data and place it on theTDM data bus (420). (Access to the TDM data bus is generally based on around robin polling process, such that only one BIM or one OMI isdesignated to transmit data on the TDM data bus at any given time.)

The sending circuit (423) of the AIMI (417) receives the digitized audiofrom the TDM source bus (421) and the communication system data from theTDM data bus (420) on a per frame basis. The sending circuit (423)places the digitized audio and the communication system data on thesource interface bus (426). After the AEB processes the digitized audioand the communication system data, the processed signals are received bythe receiving circuit (424). The receiving circuit (424), via the TDMdestination bus (422), routes the processed signals to the plurality ofsignal destinations (419).

FIG. 5 illustrates a TDM format of the source interface bus (500) andthe destination interface buses (501 and 502). The TDM format of thesource interface bus (500) comprises a train of frames, each frameconsisting of thirty-two slots. The first slot contains sync signalinformation that comprises a frame header code which indicates thebeginning of a frame. The next thirty slots comprise an eight bit PCMcode representing signals produced by the signal sources of thecommunication system. The last slot of the frame comprises an eight bitcode that typically represents a portion of a communication system datamessage. (Typically, communication system data messages require severalslots to be fully conveyed, thus only a portion is present in any oneslot.) The TDM format of the first destination interface bus (501)comprises a train of frames, wherein each frame consists of thirty-twoslots. The first slot contains a frame header code, the next thirtyslots contain an eight bit PCM code representing processed signals forsome of the signal destinations, and the last slot contains network datathat may be for any of the signal sources and/or signal destinations.The TDM format of the second destination interface bus (502) comprises atrain of frames, wherein each frame comprises thirty-two slots. Thefirst slot comprises a frame header code, while the remaining slotscontain eight bit PCM codes representing the processed signals for theremaining signal destinations. The frame header code is an eight bitsignal that is used to synchronize the communication system to the AEB(402). The best mode contemplates that the frame header code will be thebinary representation of the number eight. It should be apparent to apractioner skilled in the art that the assignment of slot locationswithin a frame may be varied from the above description withoutsubstantially altering the spirit of the present invention.

FIG. 6 illustrates a block diagram of an ambassador board (403) that, aspreviously mentioned, comprises a receiving decoder (408), a detectioncircuit (409), system data database circuitry (410), an address circuit(411), a processing circuit (412), a sending encoder (413), and signaldatabase circuitry (414). The receiving decoder (408) receives anddecodes signals and communication system data received from the sourceinterface bus (426). The signals, the sync signals, and thecommunication system data are through the receiver, or buffer, (601) andsent to a frame decoder (602). The best mode contemplates that the framedecoder (602) will be a Manchester decoder such that the sync signals,the signals, and the communication system data may be decoded, orseparated. The separated communication system data is routed to a dataextractor (603), while the separated signals are routed to an elasticstore device (604). Both the data extractor (603) and the elastic storedevice (604) utilize the separated sync signal.

The data extractor (603) which may be a field programmable gate array,extracts the communication system data contained in the last slot of theframe and stores it. (Recall from FIG. 5 that only portions of a datamessage is transmitted in any one frame.) The data extractor (603)continually extracts the communication system data from the last slotand stores it until a complete communication system data message hasbeen stored. Once a complete data message is contained with the dataextractor (603), the data extractor (603) routes the complete message tothe system data database circuitry (410). A detailed description of thesystem data database circuitry (410) will be discussed below.

The elastic store device (604), which may be a DPRAM, is used as asynchronization buffer and comprises two identical sections. Thesections are used in an alternative manner, such that when one sectionis storing signals, the other section is sourcing signals to one of theAEB signal buses (406). When a frame cycle ends, the sections reverseroles, such that the section that was storing signals in the previousframe cycle is now sourcing the signals to one of the AEB signal buses(406), while the other section is storing signals from the frame decoder(602). Thus, it takes two frame cycles to receive and place signals onthe AEB signal buses (406). If the sync signal in a communication systemis slightly different than the sync signal produced by the AEB, theelastic store device (604) will separate the sourcing and storing ofsignals by one frame cycle when the source pointer and the store pointerare at the same location in a section.

The addressing circuit (411) of the ambassador board (403) comprises adestination address generator (618) and a signal address generator(619). The destination address generator (618) typically comprises amicroprocessor, or other digital processing device, that performs thelogic functions as shown in FIG. 8. To establish addresses for each ofthe signal destinations of the respective communication system, theambassador board (403) queries the AIMI (417) of the respectivecommunication system regarding the communication system configuration(800). As previously mentioned, the communication system configurationinformation, includes, but is not limited to, the number of repeaters,number of signal sources, the number of signal destinations, the TDMslot assignments for each signal source and signal destination, the typeof each BIM, and destination information, or data. After receiving thecommunication system configuration (800), the ambassador board (403)queries the AIMI (417) regarding the number of entries, or addresses,the communication system is going to need in the destination database(801). The number of entries is based on the number of signals that eachsignal destination is to receive. For example, if the communicationsystem has fifty signal destinations and each signal destination is toreceive four signals, the number of entries, or addresses, needed wouldbe two hundred.

If a communication system (401) is connected to more than one ambassadorboard (403) (802), each of the ambassador boards verifies that it hasreceived the same information as the other ambassador board (803). Thebest mode contemplates that each communication system will beredundantly connected to the AEB via two ambassador boards. Oneambassador board will be designated as an active board, while the otherwill be designated as a backup board. If the ambassador boards do notagree on the information received from the AIMI (803), they query theAIMI again. This process will repeat until the ambassador boards agreeon the information, or until one ambassador board assumes priority. Anambassador board may assume priority either by designation or by aquality test. For designated priority, the information acquired by theactive board is given priority after several unsuccessful attempts tomatch the information. For priority based on a quality test, theambassador board having a higher quality connection to the AIMI will begiven priority, where a higher quality connection may, at least in part,be defined as lower transmission errors between the AIMI and theambassador board.

If the communication system is connected to only one ambassador board,or the ambassador boards are in agreement on the information supplied insteps 800 and 801, the active ambassador board assigns TDM slotlocations in the destination interface buses to each of the signaldestinations of the communication system (804). After the TDM slotlocations are assigned (804), the ambassador board receives from eachOMI, which is acting as a designated signal source, destinationinformation for each of the signal destinations that the OMI isaffiliated with (805). The OMI allocated the first TDM slot locationswill transmit the destination information for each of its affiliatedsignal destinations. The OMI allocated the next set of TDM slotlocations subsequently transmits the destination information for each ofits affiliated signal destination. This process repeats until all of thedestination information has been received. The address assignments forthe signal destinations will remain as established above until acommunication system changes its configuration information (806). If achange in communication system configuration is detected (806), thedestination address generator (618) repeats the process at step 801.Note that if the backup ambassador board becomes the active board, thedestination signal generator (618) detects this and sources the backupboard information as the destination addresses, without substantialinterruption.

The signal address generator (619) of the ambassador board (403)generates addresses for the signal database (616). The signal addressgenerator (619) which may be a microprocessor, or any digital processingdevice, generates the addresses as illustrated in the logic diagram ofFIG. 9. At step 900, the signal address generator (619) records theambassador board to AEB signal bus relationship. The best modecontemplates that the AEB will have thirty-two AEB signals buses and theequivalent of a card cage having thirty-two card connectors. The cardconnectors are affiliated with an AEB signal bus based on their physicallocation. For example, the first card connector is affiliated with AEBsignal bus 00000 and the thirty-second card connector is affiliated withAEB signal bus 11111. Thus, the ambassador board to AEB signal busrelationship is determined by the card connector that the ambassadorboard is plugged into. As an alternative example, each card connectormay be affiliated with two AEB signal buses such that the first cardconnector is affiliated with AEB signal buses 00000 and 10000, while thesixteenth card connector is affiliated with AEB signal buses 01111 and11111.

After the ambassador board to AEB signal bus relationship is established(900), the signal address generator (619) records the ambassador boardto communication system relationship (901). The ambassador board tocommunication system relationship is established by the physicalconnection of a communication system to a communication port. The bestmode contemplates having thirty-two communication ports, each physicallyaffiliated with a card connector, such that the first communication portis affiliated with the first card connector. (As in the alternativeexample of the preceding paragraph, the first and sixteenthcommunication ports are affiliated with the first card connector and theseventeenth and thirty-second communication ports are affiliated withthe sixteenth card connector.) Thus, the ambassador board tocommunication system relationship is established by plugging theambassador board into a card connector and coupling the communicationsystem to the corresponding communication port.

If a communication system is only coupled to one ambassador board (902),the signal address generator (619) maps a communication system to theAEB signal bus assignment based on the communication system toambassador board relationship and the ambassador board to AEB signal busrelationship (903). Specific addresses in the signal database for signalsources are determined by the AEB signal bus affiliation and the slotlocation of the signal source in the source interface bus (426). Forexample, if the signal to be stored is generated in the communicationsystem affiliated with the fifth AEB signal bus and occupies the tenthslot in the source interface bus, the signal address generator willproduce 00101 01010 (5, 10 in decimal). Thus, the signals produced bythat signal source will be addressed as 00101 01010 until its slotlocation is changed or the communication system to ambassador boardrelationship changes. If the communication to ambassador boardrelationship changes, or the AEB signal bus to ambassador boardrelationship changes (904), the process repeats at step 900.

If a communication system is coupled to more than one ambassador board(902), an active ambassador board and a backup ambassador board aredetermined (905). (The slection of an active ambassador board and thebackup board was discussed above.) Once the active and backup ambassadorboards have been established (905), the signal address generator (619)maps the communication system to the AEB signal bus assignments for boththe active ambassador board and the backup ambassador board (906).Specific addresses of the signal sources are determined as describedabove. The specific addresses remain constant until a change occurs ineither the communication system to ambassador board relationship (backupboard becomes active), or the ambassador board to the AEB signal busrelationship (907). If a change does occur (907), the process repeats atstep 900.

The signal database circuitry (414) comprises a signal database (616)which may be a DPRAM and an AEB TDM receiver (617) which may be a fieldprogrammable gate array. The AEB TDM receiver (617) is coupled to eachof the AEB signal data buses (406) and receives the signals, per framecycle, from each AEB bus and routes them, based on their respectiveaddresses, to the signal database (616). The signal database (616)comprises two sections that operate in an alternative manner. Like theelastic store (604), during a frame cycle, the signal database (616) isstoring signals received by the AEB TDM receiver (617) in one sectionand sourcing signals to the processing circuit (412) from the othersection. On the next frame cycle, the sections reverse roles, such thatthe section that was storing signals is now sourcing signals and thesection that was sourcing signals is now storing signals. The signalsare stored in either section of the signal database (616) based on anaddress generated by a signal address generator (619) of the addresscircuit (411) as described above.

FIG. 11 illustrates a typical format of the signal database (616). Thesignal database (616) comprises a plurality of address fields (1100), aplurality of PCM code fields (1101), a first section (1102), and asecond section (not shown). The second sections format will be identicalto the first section (1102), thus only a discussion the first section'sformat will be presented. As mentioned above, the signal databaseaddresses are determined by AEB bus and slot location of the signalsources. Address 00000 00000 (1103) is the address for the PCM code forslot 0 of AEB bus 0. Similarly, addresses 00000 00001 (1104), 0000000010 (1105), 10111 00000 (1106), and 10111 00001 (1107) are addressesfor the PCM codes for slot 1 of AEB bus 0, slot 2 of AEB bus 0, slot 0of AEB bus 23, and slot 1 of AEB bus 23, respectively. Each of the PCMcodes is stored during one frame cycle and sourced during the subsequentframe cycle as described above. The PCM codes of the signals may beplaced at different addresses than described above without deviatingfrom the spirit of the present invention, nevertheless, the best modecontemplates the above addressing process.

The system data database circuitry (410) comprises a first X25 PCcontroller (606), a bus arbitrator (607), a microprocessor (608), arandom access memory device or devices, (609) (RAM), read only memorydevices (610) (ROM), a destination database (611), a second X25 PCcontroller (612), a data arbitrator (613), an address bus (614), and adata bus (615). The first and second X25 PC controllers are devicesmanufactured by Motorola, Inc. The ROM (610) may be fixed ROMs, EPROMsand/or EEPROMs, and the bus arbitrator (607) may be a field programmablegate array. The destination database (611) may be a DPRAM that comprisestwo sections, where the sections operate as described below withreference to FIG. 10.

The bus arbitrator (607) allocates the ambassador board data bus (615)to either the first X.25 PC controller (606), the microprocessor (608),or the second X.25 PC controller (612). Allocation of the data bus (615)is given to the section that needs it. For example, when the first X.25PC controller (606) is sourcing communication system configuration datato the destination database (611) and the remaining communication systemdata to the RAM (609), the bus arbitrator (607) allocates the data bus(615) to the first X.25 PC controller (606). Similarly, when themicroprocessor (608) or the second X.25 PC controller (612) has data toplace on the data bus (615), the bus arbitrator (607) allocates it tothe requesting data source.

The first X25 PC controller (606), as one of its functions, receives thecommunication system data and separates it into communication systemconfiguration data and supervisory data. As previously mentioned, thecommunication system configuration data, or information, includes, atleast, destination information which contains, for each signaldestination of a communication system, information pertaining to whichsignals it is to receive and at what volume level. For example, thedestination data may indicate that a signal destination is to onlyreceive one signal from a signal source in another communication systemat full volume, or the signal destination data may indicate that asignal destination is to receive the sum of thirty signal sources fromvarious communication systems at various volume levels. The signaldestination data for each signal destination is stored in the sectionsof the destination database (611) based on an address generated by adestination address generator (618) of the address circuit (411). Thedestination address generator (618) produces addresses for the signaldestination data as described above.

The system configuration data and supervisory data are stored in the RAM(609). Unlike the destination database (611) which stores data only forthe affiliated communication system(s), the RAM (609) stores dataproduced by and/or for use by the entire communication system network(network data). The second X25 PC controller (612) that is operating intransparent mode interfaces the network data stored in RAM (609) withthe AEB data bus (405). The data arbiter (613), which may be a fieldprogrammable gate array, controls the sourcing and sinking of data toand from the AEB data bus (405) and the second X.25 PC controller (612).The sinking and sourcing of network data to and from the AEB data bus(405) will be described below.

The detection circuit (409), which may be substantially comprised in themicroprocessor (608), monitors the signals and communication system datathat is being received from the affiliated communication system. Ifsignals are not being received because the communication system is notoperably coupled to the ambassador board (403), the detection circuit(409) generates a data signal that indicates to the rest of thecommunication system network that the affiliated communication system innot actively connected to the network. The detection circuit (409) alsogenerates a mute signal that is stored in the signal database (616) atthe addresses of the signal sources of the affiliated communicationsystem.

FIG. 10 illustrates a format of the destination database (611). Thedestination database format comprises a first section (1009), and secondsection (1010), a plurality of address fields (1000), wherein, at eachaddress field, the format comprises an input control signal field (I/C)(1001), two frame control signal fields (FC1 and FC2) (1002 and 1003),three volume control signal fields (VOL.1, VOL.2, and VOL.3) (1004,1005, and 1006), a signal source bus field (1007), and a signal sourceslot field (1008). As previously mentioned, the number of entries, oraddresses, for the affiliated communication system, or communicationsystems, is determined by the number of signal sources that each signaldestination is to receive signals from. Also mentioned is that eachsignal destination of the affiliated communication system is assigned aslot location in one of the destination interface buses (427). Thus,after a frame header, or sync signal, the first entries into thedestination database (611) are for the signal source assigned to slot 1of the first destination interface bus.

If there are two communication systems affiliated with the ambassadorboard, each section (1009 and 1010) of the destination database (611)will have two entry blocks, one for each affiliated communicationsystem. The number of entries in each block is determined as describedabove, such that the total number of entries do not exceed the capacityof the destination database (611). In each entry block, the first entrywill be a frame header (1015) such that the entry blocks are in syncwith the destination interface buses of the affiliated communicationsystems. After both entry blocks have been entered, the remainingentries in the destination database are filled with null information(1013 and 1014).

As an illustrative example, assume that the ambassador board isconnected to only one communication system, that the signal sourceassigned to the first slot of the first destination interface bus hasthe following destination data (1011), and that the first section (1009)is in the storing mode. Recall that the signal destination datacomprises the signal sources that the signal destination is to receivesignals from and at what volume. For this example, the first signaldestination is to receive signals from four signal sources havingbus-slot addresses as shown. The volume levels for each signal is storedin the three volume control fields (1004, 1005, and 1006). By havingthree fields, a signal's volume level may be set at any one of eightlevels. For this example, 111 is considered maximum volume and 000 isconsidered minimum volume, however, any binary representation of minimumto maximum volumes may be used. The I/C field (1001) indicates the endof a signal destination's destination data. For this example, thatoccurs at address 000 000 000 100.

As a continuation of the above example, assume that the affiliatedcommunication system has only two signal destinations and the secondsignal destination is to receive signals from two signals sources. Thevolume levels and the bus-slot address of the signals sources are shown.Once the entries for both signal destinations have been entered, theremaining entries are filled with null information information (1013 and1014). The best mode contemplates that one section of the destinationdatabase will accommodate upto 128 signal destinations and upto 1750entries. Thus, for example, each signal destination could receivesignals from about 14 signal sources. It will be apparent to apractioner skilled in the art that the destination database may be madelarger or smaller to accommodate more or less signal destinations. Italso should be apparent that a signal destination may receive signalsfrom any number of signal destinations so long as the number doesn'texceed the capacity of the destination data base.

The null information is entered into the destination database (611) bythe microprocessor (608). Recall that the affiliated communicationsystem sends to the destination address generator (618) informationregarding the number of signal destinations within it and the number ofentries that each signal destination requires. This information may alsobe stored in RAM (609) such that it may be used by the microprocessor(608) to enter the null information into the destination database (611).The microprocessor (608) monitors the entry of destination data suchthat once it is all entered, the microprocessor (608) can enter the nullinformation.

The second section (1010) of the destination database (611) duplicatesthe information stored in the first section (1009). At start up of thecommunication system network, both sections may simultaneously receiveand store the information. Once the information is stored in bothhalves, one section acts as a sourcing section while the other acts as astoring section. Unlike the signal database, the destination database(611) does not have its sections alternate functions every frame cycle.Instead, the sourcing section of the destination database remains thesourcing section until new information (e.g. volume change, signalsource change, etc.) is received. Once the new information is stored inthe storing section, the sections switch functions. The new informationis then copied into the new storing section which then awaits anotherchange.

The processing circuit (412) of the ambassador board (403), which maycomprise a field programmable gate array, comprises a PCM to linearcoverter section (624), a summing section (625), a linear to PCM section(626), and a diagnostic latch (627). During every frame cycle, theprocessing circuit (412), under the control of the microprocessor (608),addresses the signal database (616) based on the destination informationstored in the destination database (611). The PCM codes are seriallyread from the signal database (616), converted to linear signals by thePCM to linear section (624), and summed together by the summer section(625). The summer section (625) continually adds the linear signalstogether, at the volume levels indicated, until a 1 is detected in theI/C field. Once the 1 is detected, the summer section (625) makes onefinal summation before it outputs a linear resultant to the linear toPCM section (626). The linear resultant is converted into a PCM code bythe linear to PCM section (626) and the resulting PCM code, or processedsignals, is routed to the TDM buffer (620) of the sending encoder (413).This process is repeated until each of the signal destinations have hada resulting PCM code generated for it.

As previously mentioned, signal destinations comprise AEIs that routesignals to CCMs of a console and BIMs that route signals to a pluralityof communication units. (Also recall that a BIM acts as a signal sourcetoo, such that signals can be transceived to and from the plurality ofcommunication units.) The BIMs may be of two types, the first type isused to interface the communication system to a radio repeater, and thesecond type (smart phone interface (SPI)) is used to interface thecommunication system to telephone lines. The summing of signalsdescribed above, works equally well for summed signals destined for aCCM of a console as well as to either type of BIM. If the BIM is an SPI,the communication units may comprise telephones and/or radio-telephonessuch that several telephones lines may be linked together. For example,if a communication system comprises thirty SPIs each affiliated with atelephone line, all thirty telephone lines could be conferencedtogether. In this example, each SPI would need twenty-nine signalsummations equalling a total of eight hundred and seventy summations,which is well within the capabilities of each ambassador board. Recallthat the best mode contemplates that the destination database (611) willhaving upto 1750 summation entries.

The diagnostic latch (627) of the processing circuit (412) routes eachof the resulting PCM codes to the microprocessor (608) such that thetiming and resultant may be verified. If the microprocessor detects anerror either in the timing or in the resultant, the microprocessor (608)may flag an error and shut the ambassador board down. If redundantambassador boards are used, the error flag would indicate that thebackup ambassador board should be activated.

The sending encoder (413) of the ambassador board (403) receives theprocessed signals, or resulting PCM codes via a TDM, or synchronization,buffer (620). The TDM buffer (620), which may comprise a DPRAM havingtwo sections, stores the processed signals in one section during oneframe cycle, then, in the next frame cycle, sources the processedsignals to a demultiplexer (621). The demultiplexer (621) routes theprocessed signals that are for signal destinations assigned to slots inthe first destination interface bus to a first encoder (622), and theprocessed signals that are for signal destinations assigned to slots inthe second interface bus to a second encoder (623). The first and secondencoders (622 and 623), which may be Manchester encoders, encode theprocessed signals and place the encoded processed signals in to theappropriate slots of the destination interface buses (427).

FIG. 7 illustrates a block diagram of an ambassador interface MUXinterface (AIMI) (417) that, as previously mentioned, comprises areceiving circuit (424), a processing circuit (425), and a sendingcircuit (423). The receiving circuit (424) comprises a first framedecoder (717), a second frame decoder (718), a data extractor (719), afirst elastic store (720), a second elastic store (721), a first linedriver (722), and a second line driver (723). The first frame decoder(717), which may be a Manchester decoder, receives and decodes theprocessed signals from the first destination interface bus. The secondframe decoder (718), which may be a Manchester decoder, receives anddecodes the processed signals from the second destination interface bus.The received network data is routed to the data extractor (719), whichmay be a field programmable gate array. The data extractor (719)performs in a similar fashion as the data extractor (603) of theambassador board (403), described above.

the decoded processed signals are routed from the first and second framedecoders (717 and 718) to the first and second elastic stores, orsynchronization buffers, (720 and 721), respectively. The first andsecond elastic stores (720 and 721), which may be field programmablegate arrays, function in a similar fashion as the elastic store (604) ofthe received decoder (408) in the ambassador board (403). The sourcesection of the first and second elastic stores are sourcing the decodedprocessed signals to the TDM destination buses (422), via the linedrivers (722 and 723).

The processing circuit (425) comprises a X.25 PC controller (708), a busarbitrator (709), a microprocessor (710), random access memory devices(RAM) (711), an EEPROM (712), an EPROM (716), a data transceiver (713),a dual universal asychronous receiver transmitter (DUART) (714), and awatch dog, or detection circuit, (715). (The DUART (714) is used tointerface the CEB with a CAD, such interfacing is known thus no furtherdiscussion will be given. Also the function of the watchdog circuit isknow such that no further discussion will be given.) The X.25 PCcontroller (708), which may be a device manufactured by Motorola, Inc.receives network data from the data extractor (719) of the receivingcircuit (424) and distributes it throughout the AIMI (417). Network datathat is destined for particular signal sources and/or signaldestinations is routed to a data compressor (701) of the sending circuit(423). The sending circuit (423) will be discussed below.

The bus arbitrator (709), which may be a field programmable gate array,allocates the AIMI data bus (725) among the X.25 PC controller (708),the microprocessor (710), and the data transceiver (713). When the datatransceiver (713), which may be a field programmable gate array, hasaccess to the AIMI data bus (725), it transceives data between the AIMIdata bus (725) and the CEB data bus (420). When the microprocessor (710)has access to the AIMI data bus (725), it controls the routing andstoring of the network data. When the X.25 PC controller (708) hasaccess to the AIMI data bus (725), it receives the network data from thedata extractor (719) and sources it to the rest of the AIMI (417).

The sending circuit (423) of the AIMI (417) prepares the signalsproduced by the signals sources and the data produced by thecommunication system for transmission to the ambassador board. Signalsproduced by the plurality of signal sources are received by a TDM, orsynchronization, buffer (702) which may be a DPRAM. The TDM buffer (702)operates in a similar mode as the TDM buffer (620) of the ambassadorboard. The source section of the TDM buffer (702) routes the signals toa multiplexer (705). The multiplexer (705) combines the signals receivedfrom the TDM buffer (702) with the communication system data receivedfrom the data extractor (701) and with a communication system clock thatis produced by a frame sync generator (703). An address generator (704)produces an addresses and slot assignments for each of the signalsources. The output of the multiplexer (705) is routed to an encoder(706), which may be a Manchester encoder. The encoded signals are placedon the source interface bus (426) via a line driver (707).

The preceding discussion primarily focussed on the conveyance of audiosignals between a plurality of signal sources and signal destinationsthroughout the network under the control of destination data. Thenetwork also conveys network data throughout the network. As previouslymentioned, network data comprises combinations of communication systemdata produced by each of the communication systems. One such type ofcombined communication system data is communication system configurationdata, or information. As previously mentioned, communication systemconfiguration information includes, but is not limited to, the number ofrepeaters, number of signal sources, the number of signal destinations,the TDM slot assignments for each signal source and signal destination,the type of each BIM, and destination information.

Within the communication system network, which presently contemplateshaving upto nine hundred and sixty signal sources, it would beimpractical to store, in each OMI, communication system configurationinformation of each communication system. Instead, the best modecontemplates that each OMI will store, in existing or additional memory,the communication system configuration information of the communicationsystem that it is located in and only specific communication systemconfiguration information of the other communication systems of thenetwork. Specific communication system configuration informationcomprises information pertaining to signal sources which are identifiedin the destination information of an OMI's affiliated signaldestination. For example, if an OMI in communication system 1 producessignal destination information for an affiliated AEI that has the AEBreceiving signals from BIM 1 of communication system 24, the OMI willonly store communication system configuration information pertaining toBIM 1 of communication system 24. In particular, the OMI would store thetype of BIM BIM 1 is and BIM 1's slot location within communicationsystem 24.

The best mode further contemplates that, periodically, or when acommunication system enters or re-enters the network, each communicationsystem, via its AIMI board (417), will transmit its communication systemconfiguration information to the other communication systems such thateach communication system may verify that the other communicationsystems have not changed their communication system configurationinformation. However, with present speeds of digital circuitry, it wouldbe impractical to transmit the communication system configurationinformation between all of the communication systems. Thus, within eachAIMI board (417), the communication system configuration information isconverted into a code. The communication system configuration code,which is presently contemplated to be a four bit code, is transmitted toAIMIs of the other communication systems and stored in a communicationsystem configuration code database (not shown), which may be a RAM.

FIG. 12 illustrates a process for maintaining each OMI's database ofcommunication system configuration information and for maintaining eachAIMI's communication system configuration code database. At startup,each OMI and AIMI is programmed with relevant communication systemconfiguration information and codes, however, such information and codesmay change due to a communication system changing its communicationsystem configuration information and code, a new communication systemmay enter the network, a communication system may leave the network, ora communication system may re-enter the network. At step 1201, eachcommunication system that is operably coupled to the AEB, monitors theAEB data bus for an addition of new communication system, or there-entery of a communication system, to the network. If, during acertain interval (one minute, for example), a new communication systemis not added to the network (1201), each of the communication systemsthat is connected to the AEB will transmit their system configurationcode to the AEB data bus (1202). In each communication system, the AIMIcompares the stored code of each communication system with the code onthe AEB bus (1203). If the AIMI detects that any of the codes on the AEBdata bus are different than its corresponding stored code (1204), theAIMI stores the changed code in the communication system configurationcode database (1205).

If the codes on the AEB data bus are the same as the ones stored in thecommunication system configuration code database (1204) or after the newcodes are stored (1205), each OMI determines if its specificcommunication system configuration information is up-to-date (1206). Ifthe specific communication system configuration information isup-to-date (1206), the process repeats at step (1201). If the specificcommunication system configuration information is not up-to-date (1206),each OMI that does not have up-to-date information queries only thecommunication systems that contains the specific information that theOMI stores (1207). Once the OMI receives updated specific information,it stores it (1208) and the process repeats at step 1201.

When a new communication system is added to the network (1201), the newsystem transmits a connection acknowledgement signal to the AEB (1209).After the new communication system receives a confirmation of itsacknowledgement signal, the new communication system and thecommunication systems already connected to the AEB transmit their systemconfiguration code to the AEB bus (1210). The new communication systemand the existing communication systems receive and store the codes foreach of the communication systems, including the new system (1211).After storing the codes, the new communication system transmits itscommunication system configuration information to the existingcommunication systems (1213). Each of the OMIs in the existingcommunication systems stores specific communication system configurationinformation regarding the new communication system (1213), then theprocess proceeds to step 1206 which has been described above.

If a console is equipped with a console interface CPU, or the OMI isequipped with sufficient memory, each OMI may store the communicationsystem configuration information of each communication system in thenetwork. (For a description of a console interface CPU refer toMotorola, Inc. Pub. No. R4-2-73, CENTRACOM Series II Plus ControlCenters (April, 1988).) The above process for storing specificcommunication system configuration information will be used in thisembodiment except that when a change is detected in a communicationsystem configuration code, the OMI will request and store all of thecommunication system configuration information of the system thatproduced the change.

Another type of communication system data that is transmitted throughoutthe network is BIM user data, where BIM user data comprises a list,produced by each BIM, of signal sources that have selected the BIM.Depending on the type of BIM, radio interface or telephone interface,the contents of the list will vary. For a telephone interfacing BIM(smart telephone interface (SPI)) the list will comprise entries foreach signal source that has selected the SPI and what type of telephoneconnection was requested. Presently, there are two types of telephoneconnections; private connections and public connections. A privateconnection allocates a telephone line to a requesting signal source andplaces a call to the desired destination, while excluding other signalsources from participating in the call. A public connection allocates atelephone line to a requesting signal source and places the call,however, other signal sources may participate in the call by requestingaccess to the public connection. The requesting process for either typeof telephone connection is known, thus no further discussion will bepresented.

Once a signal source requests a telephone line, an SPI will record therequesting signal source's information in a line access database (notshown). The requesting signal source's information comprises informationpertaining to the signal source's communication system and its slotlocation in its communication system. For a public connection, the SPIwould store the requesting signal source's information, store the typeof connection, and designate the requesting signal source as a primarysignal source. When other signal sources access the public connection,the SPI stores their information and affiliation with the publicconnection. In a standalone communication system, the SPI wouldperiodically send a data packet to each of the signal sources stored inthe line access database asking if the line is still needed. If any ofthe signal sources responded that the line was needed, the SPI wouldkeep the line active.

In the communication system network, it is impractical to have every SPIsend a data packet to each signal source that is accessing it, thus, theSPI periodically sends to the primary signal source, only, a data packetasking the primary signal source if the public line is still needed. Ifthe primary signal source responds that the line is still needed, theSPI keeps the line active. If the primary signal source responds that itdoes not need the line, the SPI will designate a new primary signalsource from the signal sources stored in the line access database anddelete the requesting signal source from the line access database. Oncethe new primary source has been designated, the SPI sends it a datapacket asking it if the public connection is still needed. If theprimary signal source responds that the line is needed, the SPI keepsthe line active, otherwise, the SPI designates another new primarysignal source from the line access database. The line remains activeuntil all the signal sources stored in the line access database aredesignated primary signal source and respond that the line is no longerneeded. It should be noted that more than one signal source may bedesignated as a primary signal source without deviating from the spiritof the invention, nevertheless, the best mode contemplates that only onesignal source will be designated as a primary signal source at a time.

A BIM that is operating as a radio interface in a standalonecommunication system would store each signal source that was accessingit and queries them as to whether they still need the BIM. However, in acommunication system network this would be impractical. Instead, thebest mode contemplates that each BIM will store upto three signalsources that are accessing it in an access database (not shown). When aBIM enters, or re-enters, a communication system of the network, ittransmits a data packet to all of the signal sources in the network,where the data packet asks each signal source if it has the BIMselected. The first three signal sources to respond to the data packetwill be stored in the access database. Of the signal sources stored, oneof them is designated as a primary signal source, where the primarysignal source refreshes the BIM. The primary signal source willperiodically send to the BIM a data packet indicating that it is stillselected. When the primary signal source deselects the BIM, it sends adata packet to the BIM indicating that it has deselected the BIM. Uponreceiving the deselection data packet, the BIM designates a new primarysignal source from the signal sources stored in the access database. Ifno signal sources are stored in the access database, the BIM transmits adata packet to the network that asks if any signal sources have selectedthe BIM and the above process repeats. A BIM may store more or less thanthree signal sources that have it selected without deviating from thespirit of the invention, nevertheless, the best mode contemplates that aBIM will store three signal sources.

Another type of communication system data is BIM status data, whichindicates the status of a BIM in a communication system. BIM status datamay comprise select status, auxiliary input/outputs, and link status andis stored in a BIM status database (not shown) located in each AIMI of acommunication system. Approximately every five seconds, each BIMtransmits its status to the AIMI. If the AIMI detects that a BIM'sstatus has changed, the AIMI stores the change, flags the change, andtransmits the change to the network. The AIMI also transmits the statusof BIMs that did not change their status to the network at varying timeintervals.

The varying time intervals at which the AIMI transmits non-changed BIMstatus is determined by the number of BIMs that did not change itsstatus during a predetermined time period and by a selected number BIMstatuses that the AIMI may transmit at one time. The best modecontemplates that the status of every BIM will be transmitted to thenetwork every minute and that an AIMI may transmit the status of fourBIMs at any given time. Thus, if a communication system comprises xnumber of BIMs and none of the BIMs have changed its status, the AIMIwill transmit the status of four BIMs every 4*60/x seconds. If, duringthe next varying time interval, n number of BIMs change their status,the AIMI will transmit the status of non-changing BIMs every 4*60/(X-n)seconds. For example, if the communication system has 20 BIMs and noneof them have changed their status, the AIMI will transmit the status ofthe first four BIMs stored in the BIM status database every 12 seconds(4*60/20). If, during the next varying time interval, five BIMs changetheir status, the next four non-changing BIM status will be sent 16seconds (4*60/(20-5)) after the previous status information was sent.Thus, the varying time interval will change as the number of BIM statuschanges occur. The more BIMs that change their status, the less often anAIMI has to transmit the status of non-changing BIMs.

With each communication system transmitting and receiving network data,via its affiliated ambassador board, as described above, access to theAEB data bus (405) must be controlled. The system synchronizationcircuit (404) polls each ambassadors board (403) as to whether it wantsaccess to the AEB data bus (405). The polling process may be performedin a round robin fashion based on an ambassador board's physicallocation in the card cage. When an ambassador board (403) indicates thatit wants the AEB data bus (405), the system synchronization circuit(404) stops polling the ambassador boards until the requestingambassador board is done with the AEB data bus (405). When therequesting ambassador board is done with the AEB data bus (405), thesystem synchronization circuit (404) resumes the polling process withthe next ambassador board (403) in the queue. When network data is notbeing transmitted on the AEB data bus (405), the system synchronizationcircuit (404) transmits a bus idle signal on the AEB data bus (405).

FIG. 13 illustrates a logic diagram for accessing the AEB data bus (405)by an ambassador board (403). At step 1301 an ambassador board (403)requests access to the AEB data bus (405). The ambassador board (403)will request the AEB data bus as soon as it has data to transmit on thebus (405), however, it will not get access to the bus (405) until it ispolled by the system synchronization circuit (404) (1302). Once theambassador board is granted access to the bus (1302), the microprocessor(608) of the requesting ambassador board places the line driver (624) inan active state such that pad signals being generated by the second X.25PC controller (612) are placed on the AEB data bus (405). Typically,each of the second X.25 PC controllers (612) continually produces padsignals except for when it is transmitting data onto the AEB data bus(405). The pad signals are normally prevented from being placed on theAEB data bus because the microprocessor (608) keeps the line driver(624) in a high impedance state.

The pad signals on the bus indicates to all of the ambassador boards,including the requesting ambassador board, that data is going to betransmitted on the bus. Once the microprocessor (608) of the requestingambassador board recognizes the pad signals, it enables the second X.25PC controller (612) to transmit the data onto the AEB data bus (1303).After the data has been transmitted on the bus (405), the second X.25 PCcontroller (612) resumes transmitting pad signals. If the microprocessor(608) of the requesting ambassador board received the first set of padsignals, the data, and the second set of pad signals (1304), themicroprocessor (608) places the line driver (624) in a high impedancestate such the pad signals are no longer placed on the bus (405). Oncethe liner driver is placed in a high impedance state, the systemsynchronization circuit (404) resumes placing idle signals on the buswhich indicates the end of the data transmission (1305).

If the microprocessor (608) of the requesting ambassador board did notreceive either the first set of pad signals, the data, or the second setof pad signals (1304), the process proceeds to step 1306 whichdetermines if the microprocessor (608) is receiving idle signals. If themicroprocessor (608) is receiving idle signals (1306), the ambassadorboard re-requests access to the AEB data bus (405) (1301). If themicroprocessor is not receiving idle signals (1306), the communicationsystem network is shutdown such that a system diagnostics check can beperformed.

What is claimed is:
 1. A communication system network comprising aprocessing multiplexer and a plurality of communication systems, whereineach of the communication systems comprises:a plurality of signalsources, wherein at least some of the signal sources produce signals andwherein designated signal sources of the plurality of signal sourcesproduce, at least, communication system configuration data; and aplurality of signal destinations;wherein the processing multiplexercomprises: a plurality of communication ports; signal database means forstoring information pertaining to the signals produced by the at leastsome of the signal sources of each of the plurality of communicationsystems; system data database means for storing information pertainingto the communication system configuration data produced by thedesignated signal sources of each of the plurality of communicationsystems; and processing means, operably coupled to the signal databasemeans and the system data database means, for processing, at least partof, the information pertaining to the signals stored in the signaldatabase means based on, at least in part, the information pertaining tothe communication system configuration data stored in the system datadatabase means to produce processed signals; andwherein a communicationsystem of the plurality of communication systems is operably coupled tothe processing multiplexer via at least one of the communication ports.2. In the communication system network of claim 1, the processingmultiplexer further comprises:receiving means, operably coupled to theplurality of communication ports, the signal database means, and thesystem data database means, for receiving the signals produced by the atleast some of the signal sources, for receiving the communication systemconfiguration data produced by the designated signal sources, forrouting the information pertaining to the signals to the signal databasemeans, and for routing the information pertaining to the communicationsystem configuration data to the system data database means.
 3. In thecommunication system network of claim 1, the processing multiplexerfurther comprises:addressing means, operably coupled to the plurality ofcommunication ports, the signal database means, and the system datadatabase means, for generating addresses for at least some of theinformation pertaining to the signals, and for generating addresses forat least some of the information pertaining to the communication systemconfiguration data.
 4. In the communication system network of claim 2,the processing multiplexer further comprises:signal detection means,operably coupled to the plurality of communication ports and thereceiving means, for detecting whether the receiving means is receivingsignals from the at least some of the signal sources; and muting means,operably coupled to the signal detection means and the signal databasemeans, for generating mute signals when the receiving means is notreceiving signals from at least one signal source of the at least someof the signal sources, wherein the mute signals are stored in the signaldatabase means in place of the information pertaining to the signalsproduced by the at least one signal source.
 5. In the communicationsystem network of claim 1, the processing multiplexer furthercomprises:master synchronization means, operably coupled to theplurality of communication ports, the signal database means, and thesystem data database means, for providing at least one synchronizationsignal, such that the storing of the information pertaining to thesignals, the processing of the, at least part of, the informationpertaining to the signals stored in the signal database, and routingprocessed signals to at least some of the signal destinations aresubstantially synchronously executed within a predetermined number ofsynchronization signals.
 6. In the communication system network of claim1, the processing multiplexer further comprises:sending means, operablycoupled to the plurality of communication ports, the system datadatabase means, and the processing means for sending the processedsignals to the signal destinations based on, at least in part, theinformation pertaining to the communication system configuration datastored in the system data database means.
 7. In the communication systemnetwork of claim 1, each of the communication systems furthercomprises:receiving means, operably coupled to the plurality of signalsources and the plurality of signal destinations, for receiving theprocessed signals from the processing multiplexer; and sending means,operably coupled to the plurality of signal sources and the plurality ofsignal destinations, for providing the signals produced by the at leastsome of the plurality of signal sources to the processing multiplexer,and for providing, at least, the communication system configuration dataproduced by the designated signal sources to the processing multiplexer.8. In the communication system network of claim 1, each of thecommunication systems further comprises:coupling detection means,operably coupled to the receiving means and the sending means, fordetecting operable coupling between the communication system and theprocessing multiplexer; and processing means, operably coupled to thecoupling detection means, the plurality of signal sources and theplurality of signal destinations, the receiving means, and the sendingmeans, for processing the signals generated by the at least some of theplurality of signals sources of the communication system based on, atleast in part, the communication system configuration data generated bythe plurality of signal destinations of the communication system whenthe coupling detection means detects that the communication system isnot operably coupled to the processing multiplexer.
 9. The communicationsystem network of claim 1 further comprises a plurality of signalcouplers operably coupled to the plurality of communication systems andthe processing multiplexer, wherein each of the signal couplerscomprises:source interface means for providing the signals produced bythe at least some of the plurality of signal sources to the processingmultiplexer and for providing the communication system configurationdata produced by the designated signal sources to the processingmultiplexer; and destination interface means for providing the processedsignals of the processing multiplexer to the at least some of theplurality of signal destinations.
 10. In a communication system networkcomprising a processing multiplexer and a plurality of communicationsystems, wherein each of the communication systems comprises:a pluralityof signal sources, wherein at least some of the signal sources producesignals and wherein designated signal sources of the plurality of signalsources produce, at least, communication system configuration data; anda plurality of signal destinations;wherein the processing multiplexercomprises: a plurality of communication ports; signal database means forstoring information pertaining to the signals produced by the at leastsome of the signal sources of each of the plurality of communicationsystems; system data database means for storing information pertainingto the communication system configuration data produced by thedesignated signal sources of each of the plurality of communicationsystems; and processing means, operably coupled to the signal databasemeans and the system data database means, for processing, at least partof, the information pertaining to the signals stored in the signaldatabase means based on, at least in part, the information pertaining tothe communication system configuration data stored in the system datadatabase means to produce processed signals; andwherein a communicationsystem of the plurality of communication systems is operably coupled tothe processing multiplexer via at least one of the communication ports,a method for providing inter and intra communications between theplurality of communication systems when at least some of thecommunication systems are operably coupled to the processingmultiplexer, the method comprises the steps of: a) routing the signalsproduced by the at least some of the signal sources to the signaldatabase means and routing the communication system configuration dataproduced by the designated signal sources to the system data database;b) storing the information pertaining to the signals in the signaldatabase means and storing the information pertaining to thecommunication system configuration data in the system data databasemeans; c) processing, at least part of, the information pertaining tothe signals stored in the signal database means based on, at least inpart, the information pertaining to the communication systemconfiguration data stored in the system data database means to produce,for at least some of the signal destinations, individually processedsignals; and d) routing each of the individual processed signals to therespective signal destination of the at least some signal destinations.11. The method of claim 10 further comprises, when a communicationsystem of the plurality of communication systems is not operably coupledto the processing multiplexer, the steps of:d) identifying thecommunication system that is not operably coupled to the processingmultiplexer; e) indicating to the communication systems that areoperably connected to the processing multiplexer that the communicationsystem of step (d) is not operably coupled to the processingmultiplexer; and f) storing mute signals in the signal database means inplace of the information pertaining to the signals generated by the atleast some of the plurality of signal sources of the communicationsystem of step (d).
 12. The method of claim 10 further comprises, when acommunication system of the plurality of communication systems is notoperably coupled to the processing multiplexer, the steps of:d)identifying, by the communication system of the plurality ofcommunication systems, that it is not operably coupled to the processingmultiplexer; e) processing, by the communication system of step (d), thesignals produced by the at least some of the plurality of signal sourcesof the communication system of step (d) based on, at least in part, thecommunication system configuration data produced by the designatedsignal sources of the communication system of step (d) to producedprocessed signals; and f) routing, by the communication system of step(d), the processed signals of step (e) to the plurality of signaldestinations based on the communication system configuration data. 13.The method of claim 10, wherein the processing multiplexer furthercomprises a master synchronization apparatus that is operably coupled tothe plurality of communication ports, the signal database means, and thesystem data database means, the method further comprises the steps of:e)generating at least one synchronization signal; and f) receiving thesignals from the at least some of the plurality of signal sources withina first predetermined number of synchronization signals.
 14. The methodof claim 13, wherein steps (b), (c), and (d) further comprise:b) storingthe information pertaining to the signals of step (a) in the signaldatabase means within a second predetermined number of synchronizationsignals; c) processing the information pertaining to the signals storedin the signal database means based on, at least in part, the informationpertaining to the communication system configuration data stored in thesystem data database means within a third predetermined number ofsynchronization signals to produce, for each of the at least some of theplurality of signal destinations of the plurality of communicationsystems, individually processed signals; and d) routing the individualprocessed signals to the respective signal destinations within a fourthpredetermined number of synchronization signals.
 15. A processingmultiplexer that processes communications between a plurality of signalsources and a plurality of signal destinations comprises:a plurality ofcommunication ports, wherein each communication port is, at least,operably coupled to one of the plurality of signal sources or to one ofthe plurality of signal destinations; signal database means for storinginformation pertaining to the signals produced by at least some of theplurality of signal sources; system data database means for storinginformation pertaining to the communication system configuration dataproduced by designated signal sources of the plurality of signalsources; and processing means, operably coupled to the signal databasemeans and the system data database means, for processing at least someof the information pertaining to the signals stored in the signaldatabase means based on, at least in part, the information pertaining tothe communication system configuration data stored in the system datadatabase means.
 16. The processing multiplexer of claim 15 furthercomprises:receiving means, operably coupled to the plurality ofcommunication ports, the signal database means, and the system datadatabase means, for receiving the signals produced by the at least someof the signal sources, for receiving the communication systemconfiguration data from the designated signal sources, for routing theinformation pertaining to the signals to the signal database means, andfor routing the information pertaining to the communication systemconfiguration data to the system data database.
 17. The processingmultiplexer of claim 16 further comprises:addressing means, operablycoupled to the plurality of communication ports, the signal databasemeans, and the system data database means, for generating addresses forat least some of the information pertaining to the signals, and forgenerating addresses for at least some of the information pertaining tothe communication system configuration data.
 18. The processingmultiplexer of claim 16 further comprises:signal detection means,operably coupled to the plurality of communication ports and thereceiving means, for detecting whether the receiving means is receivingsignals from each of the signal sources; and muting means, operablycoupled to the signal detection means and the signal database means, forgenerating mute signals when the receiving means is not receivingsignals from at least one signal source, wherein the mute signals arestored in the signal database means in place of the informationpertaining to the signals produced by the at least one signal source.19. The processing multiplexer of claim 15 further comprises:mastersynchronization means, operably coupled to the plurality ofcommunication ports, the signal database means, and the system datadatabase means, for providing at least one synchronization signal, suchthat the storing of the information pertaining to the signals, theprocessing of the, at least part of, the information pertaining to thesignals stored in the signal database, and routing processed signals toat least some of the signal destinations are substantially synchronouslyexecuted within a predetermined number of synchronization signals. 20.The processing multiplexer of claim 15 further comprises:sending means,operably coupled to the plurality of communication ports, the systemdata database means, and the processing means, for sending the processedsignals to the signal destinations based on, at least in part, theinformation pertaining to the communication system configuration datastored in the system data database means.
 21. In a processingmultiplexer that processes communications between a plurality of signalsources and a plurality of signal destinations, wherein the processingmultiplexer comprises:a plurality of communication ports, wherein eachcommunication port is, at least, operably coupled to one of theplurality of signal sources or one of the plurality of signaldestinations; signal database means for storing information pertainingto signals produced by at least some of the plurality of signal sources;system data database means for storing information pertaining tocommunication system configuration data produced by designated signalsources of the plurality of signal sources; and processing means,operably coupled to the signal database means and the system datadatabase means, for processing at least some of the informationpertaining to signals stored in the signal database means based on, atleast in part, the information pertaining to communication systemconfiguration data stored in the system data database means; a methodfor providing communications between the plurality of signal sources andthe plurality of signal destinations when at least some of the signalsources and the signal destinations are operably coupled to theprocessing multiplexer, the method comprises the steps of:a) routing theinformation pertaining to signals produced by each of the signal sourcesto the signal database means and routing the information pertaining tocommunication system configuration data produced by the designatedsignal sources to the system data database; b) storing the informationpertaining to signals of step (a) in the signal database means andstoring the information pertaining to communication system configurationdata of step (a) in the system data database means; c) processing atleast some of the information pertaining to signals stored in the signaldatabase means based on, at least in part, the information pertaining tocommunication system configuration data stored in the system datadatabase means to produce, for at least some of the signal destinations,individually processed signals; and d) routing the individual processedsignals to the respective signal destination of the at least some of thesignal destinations.
 22. The method of claim 21 further comprises, whena signal source of the plurality of signal sources is not operablycoupled to the processing multiplexer, the steps of:e) identifying thesignal source that is not operably coupled to the processingmultiplexer; f) indicating that the signal source of step (e) is notoperably coupled to the processing multiplexer; and g) storing mutesignals in the signal database means in place of the informationpertaining to signals generated by the signal source of step (e). 23.The method of claim 21, wherein the processing multiplexer furthercomprises master synchronization apparatus that is operably coupled tothe plurality of communication ports, the signal database means, and thesystem data database means, the method further comprises the steps of:e)generating at least one synchronization signal; and f) receiving thesignals from the plurality of signal sources within a firstpredetermined number of synchronization signals.
 24. The method of claim23, wherein steps (b), (c), and (d) further comprise:b) storing theinformation pertaining to signals of step (a) in the signal databasemeans within a second predetermined number of synchronization signals;c) processing at least some of the information pertaining to signalsstored in the signal database means based on, at least in part, theinformation pertaining to communication system configuration data storedin the system data database means within a third predetermined number ofsynchronization signals to produce, for at least some of the signaldestinations, individually processed signals; and d) routing each of theindividual processed signals to the respective signal destinations ofthe at least some of the signal destinations within a fourthpredetermined number of synchronization signals.
 25. An interfacingapparatus that is used in a communication system for interfacing thecommunication system to a processing multiplexer of a communicationsystem network, wherein the communication system comprises:a pluralityof signal sources, wherein at least some of the signal sources producesignals; and a plurality of signal destinations, wherein designatedsignal sources produce communication system data; and wherein theprocessing multiplexer comprises a plurality of communication ports andprocessing means for processing the signals based on, at least in part,the communication system data to produce processed signals, theinterfacing apparatus comprises:coupling means for coupling thecommunication system to at least one communication port of the pluralityof communication ports; coupling detection means, operably coupled tothe coupling means, for detecting operable coupling between thecommunication system and the processing multiplexer; and routing means,operably coupled to the plurality of signal sources and the plurality ofsignal destinations, for routing the signals produced by the at leastsome of the signal sources to the processing multiplexer, for routingthe communication system data produced by the designated signal sourcesto the processing multiplexer, and for routing processing signals to theat least some of signal destinations.
 26. The interfacing apparatus ofclaim 25 further comprises:processing means, operably coupled to thecoupling detection means, the plurality of signal sources and theplurality of signal destinations, for processing at least some of thesignals produced by the at least some of the plurality of signalssources of the communication system based on, at least in part, thecommunication system configuration data produced by the designatedsignal sources of the communication system when the coupling detectionmeans detects that the communication system is not operably coupled tothe processing multiplexer.
 27. In an interfacing apparatus that is usedin a communication system for interfacing the communication system to aprocessing multiplexer of a communication system network, wherein thecommunication system comprises:a plurality of signal sources, wherein atleast some of the signal sources produce signals and wherein designatedsignal sources of the plurality of signal sources produce, at least,communication system configuration data; and a plurality of signaldestinations;wherein the processing multiplexer comprises a plurality ofcommunication ports and processing means for processing at least some ofthe signals based on, at least in part, the communication systemconfiguration data to produce processed signals, a method forinterfacing the communication system to the processing multiplexer, themethod comprises the steps of: a) detecting operably coupling betweenthe communication system and the processing multiplexer; b) routing thesignals produced by the at least some of the signal sources to theprocessing multiplexer and routing the communication systemconfiguration data produced by the designated signal sources to theprocessing multiplexer when the communication system is operably coupledto the processing means; and c) receiving the processed signals from theprocessing multiplexer when the communication system is operably coupledto the processing multiplexer.
 28. The method of claim 27 furthercomprises the step of routing the processed signals of step (c) to atleast some of the designated signal destinations based on, at least inpart, the communication system configuration data.
 29. The method ofclaim 27 further comprises the steps of:d) processing at least some ofthe signals generated by the at least some of the plurality of signalsources to produce system processed signals when the communicationsystem is not operably coupled to the processing multiplexer; and e)routing the system processed signals to at least some of the pluralityof signal destinations based on the communication system configurationdata.